Honing machine



July L 194- v A. M. JOHNSON 2,247,502

HONING MACHINE Filed Dec. 30, 1938 3 Sheets-Sheet 3 54 l/76. 15a 15! ,ab j "Z3 B (Q4/benl, 07X C70/mason UHTOLIEJS Patented July 1, 1941 Fil i TE iilQE nourris insomnie Albert M. Johnson, Rockford, lli., assigner to Barnes Drill Co., Rockford, lll., a corporation of Illinois Application December 30, 1938, Serial No. 248,393

13 Claims.

` used extensively in finishing cylindrical work to accurate dimensions and with a smooth, true surface. The finishing operation is effected by relative rotation of a cylindrical abrasive tool and the work, while the supports which carry the tool and work are simultaneously relatively reciprocated totraverse the tool axially of the work. One of the supports is therefore mounted onV a suitable guideway for movement toward and from the other support. i

Various drive mechanisms have been employed in machines of the above type for reciprocating the movable support. Where relatively long work piecesare involved necessitating a long stroke of the movable support, a drive mechanism of the drumand cable type, such as that disclosed in my prior Patent No. 2,106,216 of January 25, 1938, has been found most satisfactory for Vthis purpose. The mechanism ordinarily comprises a pair of exible traction members such ascables each connected at one end to the movable support and anchored at the other end to a grooved cable drum rotatably supported at one end of the guideway. One cableileads directly to the drum. while the other cable is carried over a sheave journaled at the other end of the guidevva-y. When the cable drum is rotated, first in one direction and then in the other direction, the` cables are alternately wound up and paid out so as to pull the movable support back and forth on the guideway. y

In order to obtain the smooth shocliless reoiprocation which is peculiarly essential to precision honing, it is necessary to avoid any slack in the cables of the driving mechanism and preferably to maintain them under tension at all times during the operation of the machine. The problem of maintaining the cables under proper tension is complicated by the fact that the force required to reciprocate the movable support varies within wide limits for diiferent types and sizes oiwork, and particularly in the `case of machines which may be required to remove a substantial amount of material from the Work in a minimum of time. with this in view, one object` of 'the invention is to provide improved means for tensioning the drive cables in machines of the above general character so' as to enable the machines to operate with a high degree of accuracy under a wide variety of worhn ing conditions.

Another object is to provide improved means whereby the tension applied to the drive cables is automatically adjusted in accordance with the force required to reciprocate the movable support. l

Another object of the invention is to provide novel means for automatically removing the sludge from the coolant settling tank and for` depositing it in a suitable receptacle whichcan be quickly and easily removed or emptied.

Other objects and advantages of the invention will become apparent from the following description of the preferred embodiment illustrated in the accompanying drawings, in which:

Figure 1 is an elevational view of a honing` machine embodying the features of the invention.

Fig. 2 is a plan view of the intermediate section of the machine.

Fig. 3 is a detail View of the improved drive cable tensioning mechanism.

Fig. 4 is a schematic diagram showing the hydraulic circuits and apparatus of the machine. -i

Fig. 5 is a sectional view taken along the line 5 5 of Fig. 2, showing the settling tank cleaning apparatus in end elevation.

Fig. 6 is a detail view showing the drive mechanism for the conveyor chain which forms a part of the settling tank cleaning mechanism.

By way of illustration, the invention has been shown and Will be described hereinafter as applied to a horizontal honing machine of the type in which the honing tool is rotated and reciprocated relative to a stationary work piece. It is to be understood, however, that the invention is applicable to othertypes of honing machines and, as to certain phases, it is applicable to machine tool structures generally. Tt is also to be understood that various changes in the form, construction and arrangement of the parts constituting` the invention may be made by those skilled in the art without departing from the spirit and scope of the invention as dei-ined by the appended claims.

Referring to Fig. 1, the exemplary machine selected to illustrate the invention comprises generally an elongated base consisting of rectangular sections 'l and 8 bolted or otherwise secured together in end-to-end relation. The base section 'l is provided with a suitable horizontally disposed guideway for a reciprocatory head El which constitutes a movable support for a generally cylindrical abrasive tool or hone I 0. The tool it is carried on the projecting end of an elongated spindle or driver II journaled on the head. A motor I2 also mounted on the head 9 serves to rotate the spindle II and tool III.

The base section 9 which, in the present instance, constitutes the work support, is equipped with suitable brackets I3 for supporting work such as a cylindrical tube Ill in axial alinement with the spindle I I of the tool support. As herein shown, the brackets I3 are adjustably secured to a bed in the form of a plate I5 extending across the base section 9. The plate is provided with the usual longitudinal T-slots I5a to which the brackets may be bolted. Also mounted on the plate I5 is a coolant fixture I6 adapted to lit over the end of the work piece I9 and arranged to direct a supply of coolant into the same. The necessary coolant is supplied thereto by a motor driven pump I1 which withdraws the coolant from a reservoir I8 in the base section B and delivers it through a lter I9 and a flexible tube 29 to the xture I6.

Means isprovided for reciprocating the head 9 on the guideway to traverse the tool axially of the work. In the particular machine illustrated, this means comprisesna pair of flexible cables 2| and 22 each anchored at one end to the head and at the other end to a grooved cable drum 23 journaled in a housing 24 mounted on the end of the base section 1 farthest from the work. The cable 2l leads directly to the drum while the cable 22 is carried over a sheave 25 rotatably supported at the opposite end of the base section 1. With this arrangement, rotation of the drum 23 in one direction is effective to wind up the cable 22 and thus pull the head toward the work, while rotation of the drum in the other direction winds up the cable 2l and pulls the head toward retracted position. Any suitable means such as a rotary hydraulic motor 26 (Fig. 4) may be employed for rotating the drum 23 to reciprocate the head.

Inorder to insure smooth and shockless reciprocation of the head, the cables 2| and 22 must be held relatively taut and without any appreciable slack. Means is therefore provided for placing the cables under tension at all times while the machine is in operation. In the particular form of the invention illustrated, this is accomplished by shifting the position of the sheave 25 as required, and to this end the sheave is supported on a bearing capable of being moved longitudinally of the machine bed so as to vary the distance between the sheave and the cable drum. The movable bearing, as shown in Figs. l and 3, is in the form of a generally U-shaped bracket 21 pivoted intermediate its ends on pivot pins 28 carried on spaced vertical webs 29 (Fig. 2) formed integrally with or rigidly secured to thehbase section 1 adjacent the forward end of the guideway. The sheave 25 is held between the arms of the bracket on a shaft 30 supported on the respective arms.V As the axis of the shaft 3U is offset with respect to the pivotal axis of the bracket, movement of the sheave longitudinally of the guideway may be effected by rocking the bracket about its pivot.

Power actuated means is provided for rocking the bracketin a direction to increase the distance between the sheave and the cable drum and thereby apply tension tothe cables 2l :and 22. The power actuated means in its preferred form is hydraulically operated, and as herein. shown comprisesa cylinder 3l anchored at its closed end'between vertical ribs 32 integral with the front end wall of the base section 1. Preferably, the connection between the cylinder and the rib is provided by a pin 33 which permits limited pivotal movement of the cylinder for reasons which will appear presently. The cylinder 3l has a working piston 34 connected by a piston rod 35 with one arm of a lever 35 pivoted intermediate its ends on a pin 31 extending between the webs 29 of the base section 1.

A rigid link 3S connects the upper end of the lever 36 with the upper end of the bracket 21. As will be seen by reference to Fig. 2, the link 38 is bifurcated at one end to straddle the sheave 25 and at the other end to straddle the upper end of the lever 39. Pins 39 and 40 connect the link with the lever 36 and bracket 21, respectively. Through the connection thus provided by the lever 35 and link 38, the piston 34 is effective upon movement to the right as viewed in Fig. 3, to rock the sheave supporting bracket 21 in a counterclockwise direction and thus move the sheave 25 farther from the cable drum 23. Tension is thus applied directly to the drive cable 22 and, since the head 9 is slidably supported on the guideway, cable 2l is likewise tensioned. The cylinder 3l is enabled to accommodate itself to the lateral movements of the piston in rocking lever 34 by reason of its pivotal support on the base.

The pull exerted on the cables 2l and 22 varies, of course, in accordance with the direction in which the head is being moved and is dependent upon the resistance encountered by the tool in its rotation and relative reciprocation in engagement with the work, In order to maintain the cables under proper tension at all times, pressure fluid is supplied to the cylinder 3| variably so as to increase the force applied to the sheave supporting bracket when the cable 22 is active in moving the head 9 and to decrease such tension when the cable 2I is functioning for this purpose. Thus, the pull exerted by the cable 22 on the sheave is counterbalanced and the cables are maintained under proper tension for smooth and shockless reciprocation of the head 9.

Referring more particularly to Fig. 4, the hydraulic circuit for supplying pressure fluid to the cable tensioning cylinder and its relation to the other hydraulic circuits of the machine will be readily apparent. As shown in the drawings. pressure fluid for driving the cable drum driving motor is supplied by a pump 4I driven by a motor 42. The pump withdraws oil or other suitable fluid from a reservoir or sump 43 and delivers it under pressure to a main pressure line 44 from which a series of branch lines extend to the various machine elements and control devices. Y

One branch A5 of the main pressure line 44 extends to a reversing valve 46 of the usual and well known construction which is arranged to connect feed lines 41 and 41a of the hydraulic motor 26 alternately with the pressure line and with a drain or return line 4B leading back to the sump 43. The construction of the valve 4S is such that when its plunger is in the position shown in Fig. 4 pressure fluid is supplied to the motor through the line 41 and spent pressure fluid is exhausted through line 41a and the drain $8. Under these conditions, the motor rotates in a direction to turn the cable drum 23 counterclockwise (as viewed in Fig. 1) so as to wind up the cable 22 and thus move the head 9 toward the forward end of the guideway. The cable ZI is paid out as the cable drum. i

Upon operation ofthe valve plunger to its alternate position, pressure fluid is supplied to the motor 2E by way of the line la and spent pressure fluid isexhausted through the line il and drain 132i.` Under these conditions, the direction of the motor is reversed and likewise the direction of rotation of the cable drum Z3, so that the cable 2l is now wound up on the drum and the head 9 is drawn back to retracted position. The operation of the reversing valve le is elfected, in the present instance, by pressure fluid supplied through a branch line i9 and under control of a pilot valve 5E) operated by the head 9 in well known manner incident to its reciprocation.

In order to avoid the formation of slack in either of the driving cables as the head 9 is moved back and forth on the guideway, the inner end of the cable tensioning cylinder il! is connected directly to the main pressure line by a branch line 5l so that piston 34 is constantly urged toward the right as viewed in Fig. 4. The other end of the cylinder is 'connected by a line 53 with the motor feed line ila which carries pressure fluid only when the motor is being driven in a direction to wind up the cable El and pay out the cable 22.

When the motor 2t is operated to move the head 9 forwardly by winding up the cable 22, the feed line fila is connected to the drain as above explained, hencethe full pressure of the line iii is applied to the left end of the piston 3d. The piston acting through the rod 35, lever and 22 is wound up on the link .'lthus tends to swing the sheave supporting bracket 2l in a counterclockwise direction. against the pull exerted by the cable 22 in drawing the head forwardly. Due to the leverage provided, the pressure applied to the piston is thus enabled to counterbalance the pull of the cable 2 and to take up any slack in the cable il as it is paid out by the rotating cable drum. Moreover, it will be apparent that the force exerted on the sheave supporting bracket is proportioned to the force required to move the head forwardly since the pressure in the line flil will build up in accordance with the resistance offered to the reciprocation of the tool, that is, to the hydraulic rotation of the motor 2S.

When the motor E6 is reversed, the cable 2i is wound up to draw the to retracted.A position and cable 22 is paid out. The cable 22 therefore does not exert any substantial pull on the sheave 25, hence no counterbalancing force is required. However, it is necessary to maintain sufficient pressure on the left end of the piston 3d so as to take up any slack in the cable 22 as it is paid out from the drum. Application of the required amount of pressure is effected automatically by the introduction of pressure fluid into the right end of the cylinder 3i from the feed line itl?. Since the piston rod 35 extends through the right end of the cylinder. the active area of the right end of the piston is substantially smaller than the active area of its left end. Accordingly, only the pressure differential is applied to the sheave supporting bracket and in a direction tending to move the sheave to the left as viewed in Fig. 3. Thus the cable tensioning mechanism functions to maintain suflicient tension on the cable 22 to take up any slack that might otherwise appear as the cable is unwound from the cable drum. Further, the tension on the cable is substantially uniform throughout the return stroke of the head.

In the case of horizontal honing machines of settle out.

the above general character as well as in other types of honing machines, the pump Il is arranged to ilood the work and tool with a copious supply of liquid coolant such as kerosene, mineral seal oil or the like during the honing operation. This coolant serves both to prevent overheating of the tool and work and to carry away the metal particles removed from the work and the abrasive particles Worn from the tool. The coolant' must, of course, be perfectly clear and free of grit initially to avoid any chance of scratching or otherwise marring the surface of the work.

For reasons of economy, it is desirable to use the coolant again and again, which necessitates the removal of the solid particles before it is returned to the work. Accordingly, the coolant, after leaving the work with its entrained metal abrasive particles is caught on the bed plate i d and drain-ed into a shallow pan 55 (Figs. l and 2) set in the machine base at the `forward end of the work supporting section 1. An opening ii' in one side of the pan allows the coolant to how into a settling tank 5l in which the heavier particles of abraded material are permitted to The coolant then returns to the reservoir it through an opening 58 (Fig. 5) in the side wall of the base section 3, which opening communicates with the tank 5l at a point subtantially above the bottom thereof.

In large honing machines, and in fact in any` honing machine designed for the removal of a relatively large quantity of stock in the honing operation, the abraded material or sludge accumulates so rapidly in the settling tank that frequent shut-downs of the machine may be necessary to permit removal of the accumulated material, or else an attendant must give substantially his whole time to keeping the tank clean. Either is objectionable, since in one case it decreases the operating efficiency of the machine and, in either case, it adds materially to the cost of the honing' operation. These difficulties are avoided in the present instance by the provision of a novel conveyer for automatically removing the sludge from the settling tank, the tank being designed with a particular view of accommodating an endlessV chain conveyer for this purpose.

Referring to Figs. 2 and 5, the settling tank 5l as herein shown is of generally rectangular form and is assembled with the machine as an integral part of the base section 8. One side wall of the tank is formed jointly by a section 59 of the side wall of the machine base and by an outwardly and downwardly inclined side plate 6B welded or otherwise secured along its upper edge to the wall The other side wall of the tank is formed by a vertical plate 6i which merges into an inwardly and downwardly inclined side plate The plates E@ and S2 terminate at their lower edges in substantially vertical portions lilla and spaced apart laterally to denne a relatively narrow trough-like bottom for the tank. The lower edges of the side .plates t@ and 52 are welded or otherwise secured to a bottom plate [i3 projecting horizontally from the bas-e section 8, this plate forming the bottom of the tanl. Inwardly and downwardly inclined end plates 655 and @il close the ends of the tank.

The heavier particles of abraded material entrained in the coolant introduced into the tank settle toward the bottom of the tank and are directed into the trough-like bottom portion thereof by the converging side walls til and $2. This trough-like bottom of the tank forms a run for a chain conveyer which is arranged to carry the sludge from the tank and to deposit it in a receptacle such as a drum t6 which can be removed quickly and easily and replaced by an empty drum when full so as to avoid any necessity of shutting down the machine.

The sludge removing conveyor as herein shown is in the form of an endless chain scraper comprising an endless chain 6l to which are secured a series of transverse plates or Scrapers 6B (Fig. 6). The chain is supported by sprocket wheels so that the Scrapers are drawn along the troughlike bottom of the tank and up the inclined end wall B5 by appropriate movement of the chain. To this end, sprocket wheels 69 and IB are supported in the tank adjacent the bottom and at opposite ends thereof as shown in Fig. 1. A third sprocket wheel Il is mounted at the upper end of the tank adjacent the outer edge of the end Wall 65, thus providing two angularly related runs of chain extending parallel to the bottom plate 63 and to the end plate 65, respectively.

The sprocket wheel 'll is preferably adjustably supported to permit adjustment of the tension of the scraper chain 6l. To this end, the sprocket Wheel is keyed to a transverse shaft 'l2 (Figs. 5 and 6) journaled in bearings formed in spaced depending arms 13 of a slide 14. The slide may be dove-tailed or otherwise slidably secured on an inclined pad 15 formed on a bracket 'I6 rigid with the base section and projecting laterally therefrom to overlie the settling tank, as shown in Fig. 5. An adjusting screw 'l1 rotatably anchored to the slide '14 and threaded into a lug 18 rigid with the bracket 16 provides a convenient means of moving the slide as required. The inclination of the pad 'l5 is preferably the same as that of the end wall 65 so that adjustment of the chain may be made without moving the Scrapers 68 out of contact with the end wall of' the tank.

Any suitable means may be employed for driving the scraper chain to remove the sludge from the tank. The driving means as herein shown comprises a pawl and ratchet mechanism equipped with a hydraulic -actuator arranged to impart step by step rotating movement to the sprocket wheel 7|. As shown in Fig. 6, a ratchet Wheel 8| is keyed to the shaft 12 which carries the sprocket Wheel 'l l. Loosely mounted on the shaft l2 adjacent the ratchet is a disk 82 on which is pivoted a pawl 83 adapted to coact with the teeth of the ratchet Wheel. The arrangement of the pawl is such that when the disk is rocked about `the axis of the shaft 72 in a clockwise direction,

as viewed in Fig. 6, a similar rotative movement is imparted to the ratchet and the associated sprocket wheel 1l. Upon rotation of the disk 82 in the opposite direction, the pawl slides over the teeth of the ratchet Without moving the same. If desired, a locking pawl may be provided for preventing reverse movement of the ratchet, although ordinarily this is unnecessary as the friction of the parts is sufficient to perform this function.

The hydraulic actuator for the pawl and ratchet mechanism is arranged to rock the disk,v 65

32 PBIiOdiCally to advance the scraper chain step by step. The actuator, as herein shown, comprises a cylinder 84 rigidly mounted on the slide 'I4 which carries the sprocket and associated equipment so that adjustments of the tension of the sprocket wheel may be made without affecting the drive mechanism. The cylinder 84 is provided With a Working piston 85 having a piston rod as connected by a link s1 with an arm sa projecting radially from the disk 82.

A compression spring 89 acting on the piston normally holds it in the upper end of the cylinder. Upon introduction of pressure uid into the upper end of the cylinder, the piston is forced `downwardly against the action of the spring 89, thus rocking the disk 82 in a clockwise direction and, through the medium of the pawl and ratchet mechanism, imparting a rotative step to the shaft 'I2 and sprocket wheel 1I. When the pressure is relieved, the spring 89 returns the piston 85 to its upper position, thereby rocking they disk 82 back to the normal position shown in the drawings.

While the supply of pressure fluid to the scraper chain driving cylinder 84 may be controlled or regulated in any suitable manner, it is preferred to connect the cylinder with the general hydraulic system of the machine in a manner such that the feed movements of the chain are controlled automatically. In the particular machine illustrated, the upper end of the cylinder 84 is connected by a line 90 with the branch line 5| which in turn connects with the main pressure line 44. A line 9| leads from the lower end of the cylinder to the drain 48 and serves to carry olf any uid which may leak around the piston.

With the above arrangement, a pressure impulse is imparted to the piston B5 and the chain is advanced one step in each machine cycle. At the end of the machine cycle, the supply of pressure iiuid is cut off from the machine elements by opening a stop valve 92 which returns the fluid directly to the sump. The piston B5 is therefore relieved of pressure, thereby enabling' the spring 89 to return it to the upper end of the cylinder in which it remains until the next pressure impulse is received in the succeeding machine cycle.

It will be apparent that a more rapid feed of the chain may be obtained by connecting the cylinder 84 with a different source of pressure fluid as, for example, with the feed line 41 so that a pressure impulse is applied to the piston 85 each time the head 41 is moved forwardly. Other arrangements of the hydraulic circuit will readily suggest themselves to those skilled in the art` It will be apparent from the foregoing that the invention provides novel and advantageous means for maintaining the drive cables of a horizontal honing machine or the like under proper tension at all times so that the reciprocatory support may be reciprocated smoothly and with complete absence of shock from slack driving cables. Through the medium of a novel hydraulic actuated means, the tension of the drive cables is automatically adjusted in accordance with the resistance offered to the relative movement of the tool and Work.

The invention also provides novel means for automatically removing accumulated sludge from the coolant settling tank of a honing machine or other machine tool in which abraded material is carried away from the work by means of a stream of liquid coolant. The mechanism provided for this purpose is simple in construction,

reliable in operation and capable of maintaining the settling tank in condition for proper functioning of the machine.

I claim as my invention:

1. In a machine tool, in combination a reciprocatory support, a guideway for said support, means for reciprocating said support on the guideway comprising a drum rotatably supported at one end of the guideway, a bracket pivoted at the other end of the guideway, a sheave journaled on said bracket, a `cable extending from said support directly to said drum, a second cable extending from said support and over said sheave to the drum, power actuated means for rotating `the drum alternately in opposite directions to wind up and pay out said cables and thereby reciprocate saidV support; a hydraulic cylinder mounted adjacent said other end of the guideway, :a piston in said `cylinder operatively connected with said sheave supporting bracket, said piston `being operative when shifted in one direction to rock the bracket so as to move said sheave away from the cable drum and thereby place said cables under tension,Vv and means for supplying pressure iluid to the cylinder to shift said `piston in said one direction.

2. In a machine tool, in combination, a reciprocatory support, a guideway for said support, means for reciprocating said support comprising a drum rotatably supported at one end or" the guideway, a sheave journaled at the other end of the guideway, cabies extending from said support to said drums one of said cables being carried over said sheave whereby to move the head toward said other end of the guideway when the cable is wound up on the drum, pressure fluid operated means for rotating said drum to wind up said cable, means for adjustably supporting said sheave including a movable bearing bracket for the sheave, pressure iiuid means tending to shift said bracket in a direction opposite to the pull of said cable, and a hydraulic circuit for supplying pressure fluid from a common source to said drum rotating means and said bracket shifting means whereby the force exerted on said bracket is varied in accordance with the force required to move said support.

In a machine tool, in combination, a reciprocatory support, a guideway for said support, means for reciprocating said support comprising a drum rotatably supported at one end of the guideway, a sheave journaled at the other end of the guideway, cables extending from said support to said drum, one of said cables being carried over said sheave whereby to move the head toward said other end of the guideway when the cable is wound up on the drum, means for maintaining said cable under tension including a bearing bracket for said sheave movable longitudinally of the guideway, means for exerting suiiicient pressure on said bracket to counterbalance the pull exerted by said one cable in moving the support, and means for decreasing the force exerted on said bracket when the support is moved by the other cable.

Il. In a machine tool, in combination, a reciprocatory support, a guideway for said support, means for reciprocating said support comprising a drum rotatably supported at one end of the guideway, a sheave journaled at the other end of the guideway, cables extending from said support to said drum, one of said cables being carried over said sheave whereby to move the head toward said other end oi the guideway when the cable is wound up on the drum, means for maintaining said cable under tension including means tending `to move said sheave in a direction opposite to the pull of said cable, and means for automatically varying the pressure exerted on said sheave in accordance with the force required to move said support.

5. In a machine tool, in combination, a reciprocatory support, a guideway for said support, means for reciprocating said support comprising a drum rotatably supported at one end of the guideway, a sheave journaled at the other end of the guideway, cables extending 'from said support to said drum, one of said cables being carried over said sheave whereby to move the `head toward said other end of the guideway when the cable is woundup on the drum, a shiitable bearing bracket `supporting saidsheave, hydraulically operated means acting on said bracket to maintain said cable under tension, and means for varying the pressure exerted on'said bearing in accordance with the pull exerted on the cable by said drum. j

In a machine tool, in combination, a reciprocatory support, a guidewayforV `said support, means for reciprocating said support comprising `a drum rotatably supported at one end of the gmdeway, a sheave journaled at the other end oi the guideway, `cables extending from said support to said drum, one oi said cables being carried over said sheave whereby to move the iead 'toward said other end of `.the guideway Awhen the cable is wound up on the drum, means for adjustably supporting said sheave including a shiitable bearing bracket for the sheave, and hydraulically operated means for shifting said bracket to apply a predetermined tension to said one cable.

'7. in a nachine tool, in, combination, a reciprocatory support, a guideway for said support, means for reciprocating said support on the guideway comprising a drum rotatably supported adjacent one end or" the guideway, a sheave rotatably supported adjacent the other end of the guidcway, flexible cables connecting said .nport and said drum, one oi said cables extei ng directly to the drum and the other of said cables extending over said sheave and then to the drum, power actuaed means for rotating said drum alternateiy in opposite directions to reciprocate said support, and means for taking up the slack in said cables including hydraulically operated means tending to move said sheave away from said drum.

S. In a machine tool., in combination, a reciprocatory support, a guideway for said support, means reciprocating said support on the leway comprising a rotatably supported adiacent one end of the guideway, a member rotatably supported adjacent the other end oi the "ieway, fiexible traction members connecting support and drum, one oi said traction crs extending directly to the drum and the of said traction members extending over rotatable member and then to the drum, f actuated means for rotating said drum lately in opposite directions to reciprocate port, and means for automatically varythe tension of said traction members in accordance with the force required to rotate said drum.

9. In a machine tool, in combination, a reciprocatory support, a guideway for said support, means ici' reciprocating Said support on the guideway comprising a drum rotatably supported adjacent one end of the guideway, a sheave rotatably supported adjacent the other end of the guideway, Flexible cables connecting said support and said drum, one or" said cables extending directly to the drum and the other of said cables extending over said sheave and then to the drum, power actuated means for rotating said drum alternately in opposite directions to reciprocate said support, and hydraulically operated means for maintaining said cables under predetermined tension.

A v10. A horizontal honing machine having; in

combination,a horizontally disposed guideway, a support mounted for reciprocation on said guide- Way, a pair of flexible traction members secured to said support and extending in opposite directions therefrom generally parallel to said guide- Way, pressure fluid operated means acting through said members alternately to reciprocate the support on said guideway, and pressure fluid actuated means operating automatically to maintain the traction members under predetermined tension.

A11. A horizontal honing machine having, in combination, a guideway, a support mounted for -reciprocation on said guideway, a pair of Ilexible traction members secured to said support and extending therefrom in opposite directions, a power driven actuator acting through said members `alternately to lreciprocate the support on said guideway, and means for automatically varying the tension of the traction members in accordance With the force required to move the support.

V12. A honing machine having, in combination, a reciprocatory support, a pair of flexible traction members secured to said Ysupport and extending therefrom in opposite directions, a pressure uid operated actuator acting through said members alternately to reciprocate the support, pressure uid operated means for applying tension to said traction members, and a pressure fluid circuit for supplying pressure fluid from a common source to said actuator and said tension applying means so that the tension applied to the traction members is determined in accordance with the force required to move the support.

13. A honing machine having, in combination, an elongated base, a support mounted for reciprocation on the base, power driven support reciprocating mechanism disposed Within said base, a rotatable member atV each end of the base, a pair of flexible cables connected to said support and extending therefrom over said rotatable members respectively and to said mechanism to operatively connect the mechanism with the support, and means for automatically taking up slack in said cables comprising a pressure fluid operated device acting on one of the cables.

ALBERT M. JOHNSON. 

